Mesozoic

The Mesozoic era marks a period of dramatic evolutionary change and geological activity. The era began with the recovery from the Permian-Triassic mass extinction. The Triassic period saw the rise of the first dinosaurs, which would become the dominant terrestrial vertebrates for the remainder of the era. Other significant reptile groups, including the ancestors of crocodiles and turtles, also evolved during this time.

Throughout the Jurassic and Cretaceous periods, dinosaurs flourished in a wide variety of forms, ranging from the massive sauropods to the fearsome theropods like Tyrannosaurus rex. The first birds, evolving from small theropod dinosaurs, appeared in the Jurassic period. Mammals, which first appeared in the late Triassic, remained small and largely nocturnal during the Mesozoic, living in the shadow of the dinosaurs.

The breakup of the supercontinent Pangaea occurred during the Mesozoic, significantly altering Earth’s climate and ecosystems. The formation of new ocean basins and mountain ranges led to the development of distinct ecosystems in different parts of the world. The climate during the Mesozoic was generally warm, with no significant evidence of glaciation.

The Mesozoic era came to a dramatic end with the Cretaceous-Paleogene (K-Pg) extinction event, around 66 million years ago. This event, likely caused by an asteroid impact in what is now the Yucatán Peninsula, led to the extinction of the non-avian dinosaurs, as well as many other species, both marine and terrestrial. This extinction event paved the way for the rise of mammals and the dominance of birds in the following Cenozoic era.